Projection apparatus



Feb. 26,- 1945,

H. OSTERBEFEG ET AL PROJECTION APPARATUS Filed 1942 INVENTORS 040057525596 H14 BY PAl/Z C. I 1

TORNEY Patented Feb. 26, 1946 UNITED STATES ATENT orifice PROJECTIONAPPARATUS Harold Osterberg and Paul C. Heijn, Bufialo,

N. Y., assignors, by inesne assignments, to

Company, Southbridge,

Mass., a voluntary association Application October 5, 1942, Serial'No.460,906

American Optical,-

3 Claims.

This invention relates to projection apparatus and has particularreference to new and improved means for preventing injury to the objectprojected by said apparatus. 1 1

An object of the invention is to provide a new and improved means forpreventing injury to I the objects projected from the heat from the saidprojection appailluminating system of ratus.

Another object of the invention is to provide means for cooling orventilating the object being projected by an opaque projector which willprevent said object from being injured or damaged, from heat from'theilluminating system of the projector.

Another object of the invention is to provide means for protecting theobject to be projected against radiating heat and/or ultraviolet lightfrom the illuminating system of the projector.

{Another object of the invention is to provide means for preventing heatfrom the illuminating system of the projection apparatus from reachingthe object to be projected and means for cooling said heat preventingmeans to prevent injury thereto from said heat.

Another object of the invention is to provide With projection apparatusand particularly that type of projection apparatus adapted for theprojection of opaque objects or the like, such as postcards, pages of.books, biological materials, etc., it has been necessary that a highpower illuminating system be employed in' order to obtain the desiredillumination on the object to' obtain a successful image upon thescreen. This use of. a high power illuminating system has introduceddifliculties in thatthe heat radiatedxfrom said system sometimes causedinjury to. the material being projected and especially where suchmaterial was sensitive, such as printed postcards, dyed fabrics andbiological materials-and even though cooling systems have been providedwhereby an air stream has been forced into' the interior of the rojectoryet damage has been done to -suchsensitive materialsbecause of theamount of infra-red an ultraviolet rays emanating from said intenselight source.

It is therefore one of the prime objects of this invention to providenew and imnew and improved means for directing the coolingair currenttowards the object being pro- -jected to prevent injury thereof by heat.

Another object of the invention is to provide new and improved means forpreventing the heat f-rom the illuminating system of a projectorreaching and injuring the object being projected by a projector forprojecting opaque materials or the like.

Other objects and advantages of thefinvention will be apparent from thefollowing description taken in connection. with the accompanying drawingand itwill be apparent that many changes may be made in the arrangementof parts and details of construction without de-.

parting from the spirit of the invention as set forth in theaccompanying claims. We, therefore, do not wish to belimited to theexact details of construction and arrangement of partsshownand describedas the preferred form has been shown by way of illustration only.

, Referring to the drawing:

Fig. 1 is a side view partially in sectionv of a projection apparatusembodying the invention.

Fig. 2 is a fragmentary sectional view taken on line 2-2 of Fig. 1looking in the direction of the arrows. i

Fig. 3 is a view similar to Fig. 2 but showing a modified form of theinvention.

proved means for preventing injury to said materials which will allowthe longer projection of said materials and the projection of materialsI which is pivoted to said base at '8 and whichis normally urged towardthe under side of said casing 2 by the resilient or coil spring 9 whichis secured at one end tothe base 2 and at its opposite side'to the armor support Ill for said platen. Said platen 1 is adapted to overlie theopening H in the bottom wall of said casing to support objects to beprojectedin alignment with I said opening H whereby the said objectsmaybe projected by the reflector 6 through theopticalsystem 5 onto aprojection screen. Y

The reflector 4 assisted by the reflectors I2 is adapted to concentratethe light from the lamp 3 upon theobject l3 on the platen l to projectan image on the projection screen of the ob- Secured to the casing 2 isthe'eooling or venti- 2. i i v 2,805,501-

I instead of using a screen of a heat absorbing mung member 14 whichcomprises the fan I! adapted to be driven by the motor l8 and thiscauses an air stream to flow through the channel or canal formed by themember H and to enter said'housing 2 through an opening I! adjacent thelower rearv portion thereof to ventilate the interior of said housing. I

Over the opening H in the lower-wall of the casing 2 and in alignmentwith the platen I and material to be projected I3 is placed the rearretarding or absorbing screen or the like l8.

This heat absorbing or retarding screen may be supported by projectionsl9 secured to the walls of said housing 2 and may extend. from wall towall as shown inFig. 2 'or may be spaced from the said walls. adjacentits ends as shown "-inFig.3.

which will prevent ultraviolet and/or infra-red rays from reaching thematerial to be projected.

Suchscreen 18 may be formed with a commercial glass known as Calobar orthe commercial glass known asAklo or other similar glasses having theproperties mentioned above.

p The said screen 18 is preferably positioned as shown in Fig. 1' sothat the airxstream entering said housing through the opening II willhave a portion thereof directed toward the lower surface 20 of saidscreen l8 and the opening H in' the lower wall of the casing which willboth 0001 the lower surface 20 of the said screen l8 and the material tobe projected l3 and a portion of said air stream will be directed overthe 7 upper surface 2! of said screen l8 so that said screen l8 will becooled on both sides to preventbreakage thereof and also the air streamdirected between the lower side I! of said screen 18 and the materialto. be projected I! will cool said material l3 and prevent injurythereto by heat from said lamp 3.

It is also pointed out that as the said screen 18 maybe cooled onbothsides thereof that or infra-red and/or ultraviolet glass as describedabove the said screen I8 may be formed parent as possible in order notto interfere with the transmission of light therethrough any more thannecessary.

There are also a number of glasses on the market which retard or absorbthe infra-red and/or ultraviolet rays but are transparent and which areclear or transparent'and such glasses ma be used for said screen orplate l8. From the foregoing it will be seen that we have providedsimple, efficient and economical means for obtaining all of the objectsand advantages of the invention.

Having described our invention we claim:

1. An opaque projector comprising the combination with a projection lenssystem a reflector opticallyaligned therewith and a source ofillumination, of a horizontal conduit for cooling air defined by anupper transparent wall and a lower pivoted platen for supporting thematerial to be projected, and a blower for delivering cooling air to oneend of said conduit, the portion of said conduit including the uppertransparent wall and the pivoted platen being optically aligned. withsaid reflector and projection lens system for the projection of an imageof the material supported by said platen.

2. An opaque projector as set forth in claim 1 in which the horizontalconduit for cooling air ha a bleed opening adjacent the transparent wallfor the passage of cooling air over the upper as well as the lowersurface of said transparent wall.

3. Anopaque projector as set forth in claim 1 in which the transparentwall for the cooling vM) air conduit is a filter for selectivelyabsorbing invisible radiation from the source of illumination.

' HAROLD OS'I'ERBERG.

PAUL c. HEIJN.

